Talk:Rubens' Tube
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[edit] Move to Rubens' Tube
Since this takes its name from Heinrich Rubens, should the name of the article be "Rubens Tube" or "Rubens' Tube"? Sciprogrammer 07:12, 3 November 2006 (UTC)
- You're absolutely right, moving article now. JeffyP 20:57, 6 November 2006 (UTC)
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- To be rather technical, proper English grammar dictates that it be "Rubens's Tube" - names that end in 's' still get the apostrophe-s. --70.19.84.104 02:34, 26 August 2007 (UTC)
[edit] Original Research
I know that original research is not allowed here at wikipedia. However, I know I read the part about Ulrich Behn somewhere when writing this article. I'll try and see if I can find it again. So far, the only mention I found was in reference 3 (.doc format), where it specifically says that Heinrich Rubens "[…]profited from Behn`s idea, who had used small flames as sensitive indicators for pressure". At the very least, this shows that Behn came up with the idea for small flames as pressure indicators. Left up for debate is what his first name was and if he indeed did the research at the University of Leipzig. I'll take both these parts out for now, until more evidence is shown. JeffyP 18:38, 18 November 2006 (UTC)
[edit] Original Article
Someone wrote an instructable, and even dug out the original 1904 article by Rubens himself ! I've corrected the date and added a Ref. Better images found by URL hacking:
My German is poor - have I got this right ?
p351 shows a telescopic tube extension to vary the length. It shows flame-maximum at the closed end, which will be a velocity node - no movement , just pressure variation. Footnote credits U.Behn - presumably not the current Ulrich Behn with an email address at uni-leipzig.de !
p352 Maxima are separated by half-wavelengths (λ/2). Oddly, Rubens reports that the flame-maximum is at the closed end (as expected) for loud sounds, but with quiet sounds, the maxima and minima exchange places ! With quiet sounds, the flame-maxima are at the constant-pressure points; loud sounds give maximum flame at lowest-velocity points. It is also found (using a rotating mirror) that the flame goes from oscillating up & down at the frequency of loud sound to a steady flame with quiet sounds. Blocking most of the holes didn't change this behaviour.
p353 Below a certain frequency, the dimensions of the tube, the diameter of the holes and their number increase the apparent wavelength compared to free-space. --195.137.93.171 (talk) 05:46, 29 December 2007 (UTC)
[edit] Expanded Article in "Annalen der Physik"
Flammenröhre für akustische Beobachtungen , H. Rubens, O. Krigar-Menzel (1905) Variation of pressure due to sound ~ 0.005 Atmospheres Maximum speed ~ 2.5 m/s For 1 kHz, max displacement ~ 0.4 mm It seems that the sound pressure can be of the same order as the extra pressure due to the gas over and above atmospheric pressure ? --195.137.93.171 (talk) 01:49, 29 December 2007 (UTC)
[edit] Isn't the second picture wrong?
It seems to me that the "lambda" ruler marks up two wavelengths, not one. —The preceding unsigned comment was added by 87.99.129.29 (talk) 08:10, 9 March 2007 (UTC).
- Ya, I noticed that a while ago, and I plan on fixing it some day soon. I ordered a Rubens' Tube of my own, and I'm going to replace the current pictures with some better ones of my own. JeffyP 00:45, 11 March 2007 (UTC)
- Actually, the dagram is correct. In a wave, one wavelength is equal to a crest and a trough, or in this case, a comression and a rarefaction. Each "high point" in the Ruben's tube, is an antinode, which flutuates between the compression and rarefaction. Ther are three--Vox Rationis (Talk | contribs) antinodes to each full wavelength.--Vox Rationis (Talk | contribs) 18:01, 11 October 2007 (UTC)
- Agreed the diagram is correct - some people who don't understand standing waves assume the speed of sound in propane is halved, but I doubt that !--195.137.93.171 (talk) 01:05, 29 December 2007 (UTC)
